Evacuation and venting system for vacuum packages and vacuum chamber therefor

ABSTRACT

An evacuation and venting system and method for providing vacuum packages utilizing a vacuum chamber having two vacuum channels or ports, located at the side of the vacuum chamber, and a vacuum channel or port, located at the top of the chamber. The side vacuum channels are arranged to provide efficient evacuation of a package disposed in the vacuum chamber to allow the space between the bottom of the package and the top of the package to be evacuated without adversely affecting the sealing bars of the vacuum chamber. The vacuum chamber may be used to vacuum pack liquid-packed foodstuffs by having the top vacuum channel vent or otherwise remove the liquid from the side vacuum channels subsequent to evacuation.

United States Patent [191 Martin Sept. 3, 1974 EVACUATION AND VENTINGSYSTEM FOR VACUUM PACKAGES AND VACUUM CHAMBER THEREFOR [75] inventor:Louis F. Martin, Woodridge, NJ.

[73] Assignee: Standard Packaging Corporation,

New York, N.Y.

[22] Filed: Jan. 29, 1973 [21] Appl. No.: 327,685

[52] US. Cl 53/112 A [51] Int. Cl B65b 31/02 [58] Field of Search...53/22 A, 22 R, 112 A, 112 R [56] 8 References Cited UNITED STATESPATENTS 3,343,332 9/1967 Mahaffy et al 53/112 A X 3,509,686 5/1970 IBer'gstrom 53/112 A 3,706,174 12/1972 Young et a1. 53/112A X 3,750,3628/1973 Kishpaugh 53/22 A Primary Examiner-Travis S. McGehee Attorney,Agent, or Firm-Amster & Rothstein 5 7 ABSTRACT An evacuation and ventingsystem and method for providing vacuum packages utilizing a vacuumchamber having two vacuum channels or ports, located at the side of thevacuum chamber, and a vacuum channel or port, located at the top of thechamber. The side vacuum channels are arranged to provide efficientevacuation of a package disposed in the vacuum chamber to allow thespace between the bottom of the package and the top of the package to beevacuated without adversely affecting the sealing bars of the vacuumchamber. The vacuum chamber may be used to vacuum pack liquid-packedfoodstuffs by having the top vacuum channel vent or otherwise remove theliquid from the side vacuum channels subsequent to evacuation.

13 Claims, 6 Drawing Figures EVACUATION AND VENTING SYSTEM FOR VACUUMPACKAGES AND VACUUM CHAMBER THEREFOR This invention relates generally tovacuum systems and methods and, more particularly, to an evacuation andventing system and method for providing vacuum packages and to a vacuumchamber utilized therewith.

A multitude of prior art machines and methods have been devised forvacuum packaging products including those which form packages fromheat-sealable flexible packaging material. Such packages have found wideacceptance in the food packaging field because of the extended shelflife afforded to the packaged product by the use of such materials. Forinstance, cheeses, nuts, dried fruits, or the like, have particularlybenefited from such packaging in that these food products must beprotected from oxidizing influences, such as atmospheric oxygen, andmust be vacuum sealed for preservation purposes.

Exemplary of prior art apparatus for forming vacuum sealed packages outof heat-sealable flexible packages material is that apparatus whichincludes various operation stages or stations. For instance, at a firstoperation station, a plastic material is introduced and is formed toprovide the package bottom. The package bottom is transported to asecond operation station wherein foodstuff, or other material to bevacuum packed, is loaded into the partially formed package. The loadedpackage is then transported to a thrid' operation station where plasticmaterial is introduced to provide the top of the package and to thefourth operation station where the top of the package is partiallysealed to the package bottom. At the fifth or next operation station,two operations occur. First, the package is introduced into a vacuumchamber whereby the air in the space between the top of the package andthe bottom of the package is evacuated through the unsealed portion ofthe package by a top vacuum chammel or port in the vacuum chamber.Second, sealing bars in the vacuum chamber then seal the unsealedportion of the package in order to maintain the package in its vacuum orevacuated state. The vacuum sealed package may then be cut, etc. orotherwise packaged for shipment.

Although the above-described prior art apparatus works generallysatisfactorily, there exists the everpresent need to provide a vacuumpackaging system which operates in an improved manner. Specifically, thevacuum chambers utilized in prior art vacuum packaging systems aresubject to turbulence as the package (and the rest of the chamber) isevacuated; do not act as efficiently as is desired; and, may providevacuum sealed packages which are either not fully evacuated or are notfully sealed.

One particular difficulty has been the vacuum packaging of foodstuffswhich are packaged in a liquid, i.e., various fruit desserts. Part ofthe difficulty results from the fact that as the package is evacuatedvia the top vacuum channel in the vacuum chamber, the liquid is drawnacross the vacuum chamber seal bars (which are utilized to finally sealthe package). This cools the seal bars which, in turn, results in thefact that the seal bars often do not provide an adequate seal for thepackage.

Of course, this problem also arises where the package does not include aliquid, i.e., the flow of air across the seal bars alone may cool theseal bars to an undesirable temperature. However, this problem isaggravated when the package is liquid-packed."

Another difficult encountered in liquid-packed" foodstuffs is the factthat the liquid is drawn up in the top vacuum channel and, after thepackage has been evacuated, this liquid remains in the channel and/orflows back into the vacuum chamber. As a result thereof, undesirableexcess liquid is deposited on the top of the package resulting in apackage which is sticky to the touch. Additionally, the vacuum chamberoften fills up with excess liquid to such an extent as to render thevacuum chamber incapable of properly functioning.

Accordingly, it is a broad object of the present invention to provide anew and improved vacuum chamber for use in a packaging machine.

A more specific object of this invention is to provide a new andimproved vacuum chamber which is subject to less turbulence, operatesmore efficiently (i.e., faster) and enables the seal bars to bemaintained at their desired temperature.

Yet another object of this invention is to provide a new and improvedvacuum chamber which is free from the difficulties experienced withvacuum chambers of the prior art.

Yet another object of this invention is to provide a vacuum-packagingsystem and method for vacuum packaging liquid-packed products.

In accordance with an illustrative embodiment demonstrating objects andfeatures according to apparatus aspects of the present invention, thereis provided a vacuum chamber adapted to evacuate and seal a package andincluding a vacuum channel disposed at the top of the chamber and atleast one vacuum channel disposed at the side of the chamber.Spring-biased seal bars are provided for completing the seal between thetop and the bottom of the package after the package has been evacuated.The side vacuum channel is located such that the seal bars are notadversely cooled when the package is evacuated. The vacuum chamber isadaptedto be utilized in conjunction with an evacuation and ventingsystem for vacuum packaging liquidpackaged products, which systemincludes means for forming a bottom package member, means for loadingliquid-packed material into the bottom package member and means forpartially sealing a top package member to the bottom package member. Thesystem also includes means for evacuating the space between the top andbottom package members, through the unsealed portion of the package, andmeans for sealing the unsealed portion of the package after evacuationto maintain the package in its evacuated or vacuum state. Variouscontrol valves are provided for venting the system thereby removingliquid, or other material, drawn up into the vacuum channels duringevacuation.

In accordance with an illustrative embodiment demonstrating objects andfeatures according to method aspects of the present invention, a methodfor vacuum packaging a liquid-packed product includes the steps offorming a bottom package member, depositing liquidpacked material intothe bottom package member and partially sealing the bottom packagemember to a top package member. The partially-sealed package is thenevacuated, through the unsealed portion between the top and bottompackage members, and the unsealed portion of the package is sealed tomaintain the package in its vacuum or evacuated state. Subsequent toevacuation and final seal of the package, the system is vented in orderto remove liquid or other material drawn into the vacuum channels duringevacuation from the vacuum channels.

The above brief description, as well as further objects, features andadvantages of the present invention will be more fully understood byreference to the following detailed description of a presently preferredbut nonetheless illustrative embodiment in accordance with the presentinvention, when taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a schematic, front elevation view of the apparatus utilized inperforming the method of the present invention;

FIG. 2 is a schematic, diagrammatic view showing the system in itsevacuation mode; 7

FIG. 3 is a schematic, diagrammatic view showing the system in itsventing mode;

FIG. 4 is a side elevation view, partly in section, showing a die andthe vacuum chamber according to the present invention;

FIG. 5 is an enlarged view of part of the die and vacuum chamber ofFIG.3, showing the system in its evacuation mode; and

FIG. 6 is a top plan view, taken substantially along the line 66 of FIG.4 and looking in the direction of the arrows.

Referring to the drawings, and particularly to FIG. 1 thereof, a vacuumpackaging system, according to the present invention, is generallydesignated 10. Vacuum packaging system 10 is adapted to vacuum packfoodstuffs or other products, which foodstuffs may be in a liquid or thelike. For example, vacuum packaging system 10 may be adapted to vacuumpack fruit or other food in a liquid syrup, both the fruit and the syrupbeing vacuum-packaged and liquid-packed.

Vacuum packaging system 10 includes a chain conveyor 12 which carries aplurality of conveyor molds or dies 14. Chain conveyor 12 and dies 14are caused to be moved in a direction, as indicated by the arrow 16, byappropriate motive means (not shown). As the chain conveyor 12 and thedies 14 move in direction 16, the chain conveyor and the dies enter andleave various stages, designated A-G for convenience, wherein varioussteps in loading and forming the vacuum-sealed package is accomplished,as will be explained hereinafter.

At one side of vacuum packaging system 10, there is provided a roll 18which supplies a heat-sealable plastic packaging material 20 which isutilized to form the bottom of the vacuum-sealed package. Roll 18 may bemounted on an appropriate play-out roller 22 which is controlled bymeans (not shown) for supplying heatsealable plastic packaging material20 from roll 18 at a predetermined rate. Idler rollers'24a, 24b may alsobe provided for controlling the tension of heat-scalable plasticpackaging material 20.

Similarly, roll 26, mounted on play-out roller 28, is disposed at theother side of vacuum packaging system 10 for supplying a heat-scalableplastic packaging material 30. Appropriate means (not shown) may beincluded for controlling the rate or supply of heatsealable plasticpackaging material 30. A tensioning mechanism, generally designated 32,is provided for controlling the tension of heat-sealable plasticpackaging material 30 as this material is supplied from roll 26 rollers36, etc. Idler roller 38, disposed near the top of the flow path fordies 14, is provided to change the direction of heat-sealable plasticpackaging material 30 as this material exits tensioning mechanism 32.Thus, heat-scalable plastic packaging material 30 is caused to travel ina horizontal direction by idler rollers 38. As will be explainedhereinafter, heat-sealable plastic packaging material 30 supplied fromroll 26 is utilized to form the top of the vacuum-sealed package.

By way of general description, package bottom 40 (see FIGS. 4 and 5) isformed at stage A by forming element 42, and also at stage B and C. Atstage D, loading element 44 deposits, as indicated by arrow 46,foodstuff 48 or other products to be packaged into the formed packagebottom 40. By way of example, foodstuff 48 may be liquid-packed in asyrup or other liquid 50 (see FIG. 5). Heat-scalable plastic packagingmaterial 30, provided from roll 26, is introduced at stage E anddirected, by idler roller 38, to lie on top of the dies, thereby forminga package top 52 (see FIG. 5) for the package. A sealing element 54,located at stage E, partially seals the package top 52 to package bottom40. At stage F, a vacuum chamber 56,'according to the present invention,which is connected to a control 58 by an appropriate conduit 60,performs several functions. First, and as will be explained hereinafter,vacuum chamber 56 vacuum packs the package by evacuating the air betweenpackage bottom 40 and package top 52 through the unsealed portion of thepackage. After evacuation has been completed, sealing bars or elements,to be described hereinafter, seal the unsealed portion of the packagethereby maintaining the package in its vacuum or evacuated state.Lastly, control 58 operates in conjunction with vacuum chamber 56 tovent the vacuum chamber thereby clearing the chamber and the vacuumlines from liquid or other material which may have been drawn into thelines during the evacuation of the package. The package then travels tostage G where knife elements (not shown) I cut individual packages fromthe plurality of packages which may have been formed in a single die 14.

Referring now to FIGS. 4 and 5, the construction details of conveyormold or die 14 and vacuum chamber 56 are shown. Die 14 includes a mainbody 62 which defines die cavities 64. Two such die cavities 64 areprovided, although it is to be understood that a different number of diecavities may be provided, if so desired. Die cavity 64 may includespacer elements (not shown) having a shape which conforms to the diecavity and which allows the die cavity to form packages of varioussizes, the size depending on the shape of the spacer element insertedinto the die cavity. Die body 62 also defines a plurality of bottomvacuum channels 66a 66d which are connected, via a common bottom vacuumchannel 66e, to a fitting 70 and a hose 72. As will be explainedhereinafter, hose 72 is adapted to be connected to a source of vacuumsuch that bottom vacuum channels 66a 66d exert a vacuum force on thebottom of cavity 64 thereby maintaining package bottom 40 at the bottomof the cavity during the various stages in vacuum packaging system 10.

Die 14 includes top clamps 74, disposed at the top of the die, forclamping package bottom 40 to the top of the die (see FIG. 5). Topclamps 74 are associated with top clamp release mechansims (not shown)which operate to release the top clamps after the package has beenevacuated, vacuum sealed and vented. Die 14 may also include a rubbercushion or gasket 76 which insures that a proper seal will be obtainedas vacuum chamber 56 engages die 14 to evacuate and vacuum seal thepackage. Gasket 76 also functions to insure that a proper seal isprovided between vacuum chamber 56 and die 14 during the venting mode ofvacuum packaging system 10. Another rubber cushion or gasket 78 insuresthat an adequate seal is made between package top 52 and package bottom40 as sealing bars or elements, to be described in more detailhereinafter, carried by vacuum chamber 56 move down to cooperate wth dic14.

Vacuum chamber 56 includes a housing 80 which is adapted to be moveddownwardly, by appropriate motive means (not shown) to engage die 14(compare FIGS. 4 and 5 Housing 80 defines a top vacuum channel or port82, located at the top of housing 80, which channel is adapted toreceive a fitting 84 and hose 80. Housing 80 includes a top wall 81 andside walls 83. As will be explained hereinafter, although hose 86 isadapted to be connected to a vacuum source, the primary function of topvacuum channel 82 is to enable air, or the like, to be introduced intovacuum chamber 56 during the venting mode of the system thereby enablingfluid or other excess material to be vented out, of vacuum chamber 56and the vacuum lines associated therewith.

The evacuation of the package, i.e., the air between package bottom 40and package top 52, is provided through side vacuum channels or ports88. Specifically, vacuum chamber 56 includes side vacuum channels orports 88, disposed along side wall 83 of the vacuum chamber, which sidevacuum channels each define a plurality of side channel portions 90 (seeFIG. 5 and FIG. 6), each of which are adapted to cooperate withcorresponding side channel portions 92 defined in housing 80 (see FIG.5). Side channel portions 90 open into a common side chamber 94 which isadapted to receive a fitting 96 and a hose 98 (see FIG. 6). As will beexplained hereinafter, hose 98 is connected to a vacuum source and,accordingly, it will be appreciated that the vacuum source-provides thenecessary vacuum for evacuating the space between package bottom 40 andpackage top 52, the air being withdrawn through the various side channelportions 90 and the side chamber 92 of side vacuum channels 88.

Vacuum chamber 56 also includes sealing bars 100 which are adapted tomove downwardly from the position indicated in FIG. 5 such that sealingprojections 102, subsequent to evacuation of the package, seal theunsealed space between package bottom 40 and package top 52.Specifically, sealing bars 100 are springbiased and are adapted to moveagainst spring elements 104 connected, at one end thereof, by rivets 106to housing 80, to enable sealing projections 102 to cooperate withgasket 78, thereby completing the seal between package bottom 40 andpackage top 52 to thus maintain the evacuated or vacuum-sealed state ofthe package.

Sealing bars 100 include heating elements 108, such a wire filaments orthe like, which heating elements are adapted to be connected to anappropriate heating source in order to heat sealing projections 102 tothe necessary temperature required for the sealing projections to meltheat-scalable plastic packaging materials 20 and 30, thereby sealing thepackage top and bottom. It is apparent that if sealing projections 102are not maintained at this requisite temperature, package top 52 willnot be fully sealed to package bottom 40 resulting in a faulty packagelacking the desired vacuum-seal. As will be indicated hereinafter, oneadvantage of vacuum chamber 56 is that the package is evacuated throughthe side vacuum channels 88 thereby providing a path which does notadversely cool sealing projections 102. Sealing bars include arms 110which are adapted to move the sealing bars in the vertical direction byappropriate motive means (not shown) sufficient to overcome biasingspring 104. The motive means may move sealing bars 100 in the downwarddirection only, the bars returning to their raised position, illustratedin FIGS. 4 and 5, by the action of the biasing spring or, in thealternative, the motive means may move the sealing bars upwardly as wellas downwardly.

As indicated hereinbefore, vacuum chamber 56 is adapted to be controlledby control mechanism 58, the operation of which is schematicallyindicated in FIGS. 2 and 3. Specifically, control mechanism 58 includesa vacuum source, such as a vacuum pump 112, which is adapted to becontrolled by a cam-operated valve 114. Cam-operated valve 114, which iscontrolled by a cam 116 and cam-follower 118, also controls an inletport 120. When vacuum packaging system 10 is in the evacuation mode(FIG. 2), valve 114 functions to enable vacuum pump 112 to evacuatevacuum chamber 56. On the other hand, when vacuum packaging system 10 isin the vent mode (FIG. 3), valve 114 operates to enable air to flow intochamber 56 from an inlet port 120, as will be explained hereinafter.

Hose or line 72, connected to bottom vacuum channels 66a 66c, hose orline 86, connected to top vacuum channel 82, and hoses or lines 98,connected to side vacuum channels 88, are coupled to a manifold 122which is connected to cam-operated valve 114. A plurality ofpressure-actuated valves 124, 126, 128 are located, respectively, inhoses 86, 72 and 98 for controlling the flow of air through the hoses.By way of example, valve 128 may include a valve member 128a, which isspring-biased by a spring element 28b, to close a valve head 128C.Accordingly, valve 128 functions to prevent the flow of air, forexample, from inlet port back to pressure chamber 56, i.e., this valve Pevents air flow from left to right in hose 98 as viewed in FIG. 3. Onthe other hand, valve 128 allows the flow of air from right to left inhose 98 such as flow of air from pressure chamber 56 caused by vacuumpump 112, since air flow in this direction is sufficient to overcome thebias of spring element 128b to open valve head 1280.

Valve 126 is of substantially similar construction and includes a valvemember 126a, a spring element 126b and a valve head 126c which arearranged to allow the fiow of air from vacuum chamber 56, i.e., fromright to left in hose 72, but which functions to close valve head 1260to prevent substantial flow of air back into the vacuum chamber, i.e.,from left to right in hose 72. However, valve 126 is slightly modifiedto include a small opening or aperture 126d defined in valve head 126C.Thus, a small amount of air (indicated by the dashed arrows in FIG. 3)may flow back to vacuum chamber 56, i.e., from left to right in hose 72,notwithstanding the fact that this valve is closed Valve 124 is ofidentical construction to valve 126 and includes a valve member 124a, aspring element l24b and a valve head 124a having a valve opening oraperture 124d defined therein. Valve 124 is disposed in hose 86 in amanner to allow opposite flow as compared to valve 126; that is, valve124 allows air flow to vacuum chamber 56, as indicated by the solidarrows going from left to right in FIG. 3, but allows only a small flowof air, indicated by the dashed arrows going from right to left in FIG.2, in the opposite direction.

Hoses 98 (one connected to each side of channel 88), also include bleedvalves 130 and a liquid trap 132, disposed between the bleed valves andvalve 128, which is adapted to act as a reservoir for storing any liquidor syrup 50 which is drawn into hoses 98 during the evacuation mode.

The operation of vacuum packaging system 10 may be understood byconsidering the travel of a typical'die 14 from stage A to stage G, itbeingunderstood, however, that all operations of vacuum packaging system10 take place simultaneously, so that while one package may be atloading station D, another package may be at evacuation, final seal andventing stage F, etc.

Heat-scalable plastic packaging material 20, supplied from roll 18, isplaced on die 14 with top clamps 74, at

the top of die 14, holding the heat-scalable plastic packaging materialin place. At stage A, a conventional heating element 42 heats theheat-scalable plastic packaging material causing the material to becomemalleable in shape. The die proceeds to stage B where suction isapplied, for example, via hose 72, causing material 40 to be drawn intodie cavities 64 (two packages may be formed in die 14 since this dieincludes two die cavities; however, it is readily apparent that othernumbers of die cavities may be chosen to be formed in die 14). Die 14proceeds to stage C where material 20 is allowed to cool within the diecavity thereby forming package bottom 40.

At stage D, a predetermined amount of foodstuff 48, which may be inliquid or syrup 50, is deposited or loaded into the formed packagebottom by a loader 44.

Die 14 continues to move to stage E where heatsealable plastic packagingmaterial 30, supplied from roll 26, is placed on die 14. Material isadvantageously chosen to be of a width sufficient for this material torest on the inner ends of top clamps 74 as the material is placed on die14 (see FIGS. 5 and 6). Sealing element 54 then partially sealsheat-sealable material 20 to heat-scalable material 30. In other words,and as indicated in FIG. 6, sealing element 54 seals package top 52 topackage bottom 40, at the top of die 14, thereby forming a package lipor edge 134a along three sides and part of a fourth side of the package.However, it should be noted that although the sealed portion 134aextends substantially around the top or lip of the package, package top52 and package bottom 40 remain unsealed, as indicated at 134b, whichunsealed portion of the package is adjacent top clamp 74. As will beexplained in more detail hereinafter, vacuum chamber 56 evacuates thepackage throughv this unsealed package portion.

Die 14 is then transported to stage F such that the die is positionedbeneath vacuum chamber 56, as illustrated in FIG. 4. As will now beexplained, evacuation, final sealing and, for the case where thefoodstuff is packaged in a liquid,.venting, is accomplished at stage P.

As indicated hereinbefore, the air between package bottom 40 and packagetop 52 is evacuated through the unsealed portion 134b of the package.Specifically, and referring to FIGS. 2, 5 and 6, vacuum chamber 56 ismoved downwardly, by appropriate motive means (not shown), from theposition illustrated in FIG. 4 to the position illustrated in FIG. 5such that housing engages die 14 at gasket or sea] 76 thereby providingan airtight seal between the vacuum chamber and the die. Note that withvacuum chamber 56 in this position, sealing bars 100 have not movedrelative to housing 80 and, therefore, the sealing bars remain in theirinoperative position relative to die 14.

With vacuum chamber 56 in its evacuation mode position (illustrated inFIG. 5), the vacuum chamber is evacuated. Specifically, cam 116 controlscamoperated valve 114 to enable vacuum pump 112 to withdraw airfrom thevacuum chamber. Thus, a strong vacuum is applied to hoses 98 such thatthe air between package bottom 40 and package top 52 is withdrawnthrough the unsealed portion 134b of the package. The majority of thisair (as well as the majority of the air in vacuum chamber 56, that is,the air between the top of the die 14 and housing 80) is withdrawn, viathe side vacuum channels 88. This is indicated by the solid arrowsadjacent hoses 98 in FIG. 2 as well as the arrows indicating evacuationin FIGS. 5 and 6. I With vacuum chamber 56 in the evacuation mode, airis also withdrawn from hose 72 (see FIG. 2), such that package bottom 40is maintained contiguous with cavity 64. Thus, the vacuum applied tohose 72 insures that package bottom 40 will not flex or buckle as thespace between the package top 52 and the package bottom 40 is evacuated.

With vacuum chamber 56 in this state, a small amount of air is alsowithdrawn from chamber 56 via I hose 86 connected to the top of thevacuum chamber.

Specifically, and referring to FIG. 2, although valve 124 is nominallyclosed when the vacuum pump is operative, a small amount of air(indicated by the dashed-arrows in FIG. 2) is allowed to pass throughaperture 124d in the valve. By way of example, 90 or percent of the airwithin vacuum chamber 56 is withdrawn through side vacuum channels 88,while only 5 or 10 percent of the air is withdrawn through top vacuumchannel 82.

The advantages provided by vacuum chamber 56 over prior art vacuumchambers may be readily appreciated by reference to FIG. 5. As indicatedby the arrows in FIG. 5, during the evacuation mode of vacuum chamber56, the air between package bottom 40 and package top 52 is evacuated,through the unsealed portion 134b of the package, and is drawn throughside vacuum channels 88 to hoses 98. Hoses 98 also withdraw much of theair in the rest of the vacuum chamber, i.e., the air between housing 80and the die top. Since the unsealed portion l34b of the package is inclose proximity to the side vacuum channels, the air between packagebottom 40 and package top 52 may be evacuated quickly and efficiently.

In addition to the evacuation of air from the package, vacuum pump 112also pulls out liquid 50 through the unsealed portion 134b of thepackage. In addition to clogging the hoses (a problem which isalleviated during the venting mode which will be discussed hereinafter),the flow of liquid in prior art vacuum chambers (that is, chambers wherethe evacuation of the package is via a top channel similar to port 82)is around the sealing bars and this, in turn, cools the temperature ofthe sealing bars often to a temperature wherein the sealing bars do notfunction properly to provide a final seal for the package. However,according to the present invention and as indicated in FIG. 5, anyliquid withdrawn through the unsealed portion 134!) of the package, doesnot flow around the sealing bars 102, but rather, is directed by packagetop 52, spring 104 and top clamp 74 to the side channels 88. Thus, thesealing bars in vacuum chamber 56 are not cooled to an extent comparableto existing vacuum chambers-It sbould be noted that the problem ofcooled sealing bars (remedied by chamber 56) is a problem even in thosecases where only air is drawn over the sealing bars. This problem isaggravated, however, when the product is liquid-packed, i.e., liquid isdrawn across the bars. Not only does this cool the sealing bars, but itrenders them sticky, etc.

Relatively no liquid is withdrawn via hose 86 since top channel 82 isrelatively far removed from the unsealed portion of the package andsince little vacuum pressure is applied to the top channel as a resultof valve 124 which is nominally closed. However, the S or 10 percentvacuum applied to this port does, as indicated in FIG. 5, withdraw someair from the space between package top 52 and housing 80 of the vacuumchamber. As a result thereof, turbulence is greatly reduced in vacuumchamber 56 during the evacuation mode.

After the package has been evacuated, but with housing 80 still in theposition illustrated in FIG. 5, sealing bars 100 move downwardly,relative to the housing, against the action of spring 104 such thatsealing projections 102 seal the unsealed portion 134b of the package.Sealing bars 100 operate in an efficient manner to provide an edequateseal since the bars have not been cooled, by the flow of liquid (or air)around projections 102, in a manner existing in prior art vacuumchambers. Thus, package top 52 is now completely sealed to packagebottom 40 thereby maintaining the package in its vacuum-packed orevacuated state. After the package has been fully sealed, sealing bars100 move upwardly, relative to stationary housing 80, to resume theposition illustrated in FIG. 5.

As indicated hereinbefore, particular problems arise when foodstuffs 48are liquid-packed. Specifically, aside from the cooling of the sealingbars, it is apparent that when conventional vacuum chambers, havingmerely a top vacuum channel or port (comparable to top vacuum channel orport 82) is utilized, liquid 50 is withdrawn through this channel intohose 86. As a result thereof, when the vacuum source is renderedinoperative, much of this liquid rushes back into the vacuum chamberand, particularly, much of this liquid is deposited on the sealedpackage top. Not only will accumulation of liquid in the vacuum chamberrender'the vacuum chamber inoperative, but even a small amount of liquiddeposited on the top of the package renders the package sticky orotherwise unattractive to the consumer. Accordingly, stage F of vacuumsystem 10 includes a venting mode which enables the vacuum packagingsystem to overcome the disadvantages experienced in systems according tothe prior art.

The venting mode of vacuum packaging system 10 is illustrated in FIG. 3.Specifically, after the package has been evacuated at stage F and fullysealed at stage F, housing of the vacuum chamber and sealing bars remianin the position illustrated in FIG. 5. With these components of vacuumchamber 56 in this position, cam-operated valve 114 is controlled, forexample, by cam 1 16, to disconnect vacuum pump 112 from manifold 122and to connect inlet port to the manifold. 'Since the inside of vacuumchamber 56 is at less than atmospheric pressure (along with hoses 72, 86and 98 associated therewith), air starts to rush into the hoses towardsthe vacuum chamber. The rush of air to the hoses is controlled by thevarious pressure valves 124, 126 and 128 as will now be explained.

Considering first the flow of air in hose 86, air from inlet 120 causesvalve 124 to open by forcing valve member 1240 against spring element124b. As a result thereof, a relatively large amount of air flows intochamber 56 via top channel 82. Thus, the flow of air through hose 86during the venting mode is greater than (and in the reverse directionfrom) the flow of air through this hose during the evacuation mode(compare the arrows in FIGS. 2 and 3). This flow or rush into the vacuumchamber vents the liquid (or other material) inside hoses 98.

Specifically, and considering the flow of air in hose I 98, although airstarts to flow from inlet 120 into the hose, i.e., from left to right inFIG. 3, valve 128 is rendered closed during the venting mode (comparethe position of this valve in FIGS. 2 and 3) and, since this valve doesnot include a small opening or aperture in valve'head 128e, the valveprevents the air from inlet 120 from flowing into the vacuum chamber.However, as air .rushes into the vacuum chamber from top channel 82, thepressure differential between the inside of the vacuum chamber (now ator near atmospheric pressure) and the pressure in hoses 98 (near vacuum)causes the air, as indicated by the arrows in FIG. 3, to rush into hoses98. It should be noted that the flow of air in hoses 98 during theventing mode is in the same direction as the flow of air through thishose during the evacuation mode (compare FIGS. 2 and 3). As a resultthereof, any remaining liquid in hoses 98, that is, liquid which has notbeen collected by trap 132 during the evacuation mode, is forced to trap132 and collected therein. Thus, the air introduced to vacuum chamber 56at top channel 82 acts to vent or remove the liquid remaining in hoses98 during the venting mode. It will be appreciated, however, that as airis introduced from hose 86 into the vacuum chamber, no liquid isdeposited from this hose onto the top of the package since no liquid (orrelatively no liquid) is drawn into hose 86 during the evacuation ofpackage substantially all liquid is drawn into hoses 98.

Lastly, considering the flow of air in hose 72, although valve 126 is inits nominally closed position during the venting mode, this valve'doesallow a relatively small amount of air (indicated by the dashed-arrowsin FIG. 3), to flow from inlet 120 to the bottom of die 14.Specifically, this small amount of air removes the vacuum in hose 72and, consequently, the sealed package may be easily removed from die 14,for example, after the package is cut to stage G. If hose 72 continuedto apply a vacuum to package bottom 40, difficulty would be encounteredin removing the package. On the other hand, if a large amount of air isfree to flow to the bottom of the package, the package may well bejarred from cavity 64 which may result in improper cutting of thepackage at'stage G. I

In order to provide a more complete understanding of the presentinvention, a typical operational sequence will now be described. A I

Package bottom 40 is formed at stages A, B and C of vacuum-packagingsystem by heating heatscalable plastic packaging material 20 at stage A,drawing the material into cavity 64 at stage 8 (for example, by applyingsuction to hose 72) and by allowing the material to cool at stage C. I

At stage D, a predetermined amount of material to be packaged is loadedinto the formed package bottom, that is, into the material receivingcavity formed by the package bottom. By way of example, this materialmay be foodstuff desired to be liquid-packed, i.e., packed in a liquid.

At stage E, heat-scalable plastic packaging material 30 is introducedand caused to cover the filled package, thereby providing a package top.Additionally, package top 52 is partially sealed to package bottom40 atstage The die is then transportedto stage F wherein evacuation, finalsealing and optional venting occurf Specifically, vacuum chamber 56moves downwardly to cooperate with die 14, thereby providing an airtightchamber. Control mechanism 58 functions to connect vacuum pump 112 tothe vacuum chamber. As a result of the pressure valves 124, 126 and 128,vacuum is applied to the bottom of the cavity (via hose 72) therebymaintaining the package in place in the cavity; the air in the spacebetween package top 52 and package bottom is evacuated through theunsealed portion 134b of the package with this air, the majority of theair in the rest of the vacuum chamber, i.e., the air between package top52 and housing or body 80, and some liquid in the package beingwithdrawn through side channels 88 by the application of vacuum to hoses98. A relatively small amount of air, primarily from the vacuum chamber(and not from the package) is withdrawn through top channel 82 by theapplication of a lesser force of vacuum to hose 86. It will beappreciated that this small amount of airwithdrawn via channel 82lessens turbulence in the vacuum chamber. It will also be appreciatedthat both the air and the liquid drawn from the package is directed toside channels-88, which are in close proximity to the unsealed portionof the package; As a result thereof, not only is the package evacuatedquickly and efficiently, but the withdrawn liquid does not cool thesealing bars or otherwise render them sticky or inoperative. Much'of theliquid drawn into hoses 98 during the evacuation mode is collected intrap 132.

After the package has been evacuated, station F provides a final sealingmode in which sealing bars 100 move. downwardly to seal the unsealedportion of the package thereby maintaining the package in its vacuum"state.

After the venting and final sealing mode, an optional venting mode maybe provided at stage F. Specifically, control mechanism 58 functions toallow air to rush into hoses 72, 86 and 98. However, valvesl24, 126 and128 function to control the flow of this air. Specifically, the flow ofair in hose 86 is increased and reversed in direction as compared to theflow of air in hose during the evacuation mode thereby allowing the airto rush into vacuum chamber 56 via top channel 82. On the other hand,valve 128 functions to close hoses 98 thereby enabling the air rushinginto the vacuum chamber to continue flowing in hoses 98 in the samedirection as the flow of air in these hoses in the evacuation modeplnother words, the flow of air into vacuum chamber 56 vents any remainingliquid in hoses 98, which liquid is collected at trap 132. The ventingmode also provides a small amount of air which is introduced, via hose72, to the bottom of the cavity. This enables the packages to be quicklyremoved.

The package may be cut from the mold at stageG.

Obviously, other modifications of the present invention are possible inlight of the above teachings. For example, vacuum chamber 56 may beutilized with other systems since the vacuum chamber, in and of itself,operates efiiciently and with less turbulence then vacuum chambersheretofore available in the prior art. Similarly, this system mayinclude additional air pumps, for example, to aid in the introduction ofthe air into the vacuum chamber during the venting mode. Still further,although the embodiment disclosed has been explained with reference to aliquid-packed foodstuff, it will be appreciated that the invention hasapplication to other types of packaged materials. For example, if thepackage is granular in nature, it is the material itself which is drawnup during the evacuation mode; and this material may be vented from thelines during the venting mode. Additionally, this system may be utilizedwith otherstages, for example, a detectable gas or the like may beintroduced into the package prior to the final seal thereof in order todetect leaks or the like in the package. It is to be understood,therefore, that the embodiment described is merely an example of theprinciples of the invention. Additional embodiments may be devised bythose skilled in the art without departing from the spirit or scope ofthe present invention.

What is claimed is:

1. An apparatus for packaging a material comprising means for providinga first package member defining a material-receiving cavity, means fordepositing said material in said material-receiving cavity, means forproviding a second package member, means for partially sealing saidfirst package member to said second package member and for defining anunsealed package portion, means including a first conduit for evacuatingsaid package through said unsealed package portion, means for sealingsaid unsealed package portion thereby maintaining said package in itsevacuated state, and means including a second conduit for venting saidfirst conduit by introducing air into said second conduit.

2. The invention according to claim 1 wherein said means for evacuatingsaid package further includes a vacuum chamber adapted to be connectedto a source of vacuum for withdrawing at least the air between saidfirst package member and said second package member.

3. The invention according to claim 2 wherein said vacuum chamberincludes at least two channels adapted to be connected to said firstconduit and said second conduit, respectively.

4. The invention according to claim 3 wherein said secondconduitincludes valve means for limiting flow of air from said vacuum chamberto said source of vacuum and for permitting flow of air to said vacuumchamber, said first conduit including valve means for permitting flow ofair from said vacuum chamber to said source of vacuum and for limitingflow of air to said vacuum chamber.

5. The invention according to claim 3 wherein said means for ventingsaid vacuum chamber includes means for providing a source of air andsaid first and second conduits define a venting path from said source ofair to said second conduit to said vacuum chamber and from said vacuumchamber to said first conduit.

6. The invention according to claim 5 wherein said means for evacuatingsaid package includes means for withdrawing air from said vacuum chamberinto said first conduit in a first predetermined direction.

7. The invention according to claim 6 wherein said venting meansincludes means for introducing air into said vacuum chamber and forcausing said air to flow from said vacuum chamber through said firstconduit in the same direction as the flow of air in said first conduitduring evacuation of said package.

8. The invention according to claim 7 wherein said first conduitincludes means for trapping material withdrawn from said vacuum chamber.

9. The invention according to claim 8 wherein said means for ventingsaid vacuum chamber includes means for causing the material remaining insaid first conduit subsequent to evacuation of said package to movetoward said trap means.

10. The invention according to claim 1 further comprising means formaintaining said package in proper position relative to said vacuumchamber.

11. The invention according to claim 10 wherein said means for keepingsaid package in proper position includes means for applying a vacuum tosaid package.

12. The invention according to claim 1 1 further comprising means forremoving said package.

13. The invention according to claim 12 wherein said means for removingsaid package includes means for applying air pressure against saidpackage.

1. An apparatus for packaging a material comprising means for providinga first package member defining a material-receiving cavity, means fordepositing said material in said materialreceiving cavity, means forproviding a second package member, means for partially sealing saidfirst package member to said second package member and for defining anunsealed package portion, means including a first conduit for evacuatingsaid package through said unsealed package portion, means for sealingsaid unsealed package portion thereby maintaining said package in itsevacuated state, and means including a second conduit for venting saidfirst conduit by introducing air into said second conduit.
 2. Theinvention according to claim 1 wherein said means for evacuating saidpackage further includes a vacuum chamber adapted to be connected to asource of vacuum for withdrawing at least the air between said firstpackage member and said second package member.
 3. The inventionaccording to claim 2 wherein said vacuum chamber includes at least twochannels adapted to be connected to said first conduit and said secondconduit, respectively.
 4. The invention according to claim 3 whereinsaid second conduit includes valve means for limiting flow of air fromsaid vacuum chamber to said source of vacuum and for permitting flow ofair to said vacuum chamber, said first conduit including valve means forpermitting flow of air from said vacuum chamber to said source of vacuumand for limiting flow of air to said vacuum chamber.
 5. The inventionaccording to claim 3 wherein said means for venting said vacuum chamberincludes means for providing a source of air and said first and secondconduits define a venting path from said source of air to said secondconduit to said vacuum chamber and from said vacuum chamber to saidfirst conduit.
 6. The invention according to claim 5 wherein said meansfor evacuating said package includes means for withdrawing air from saidvacuum chamber into said first conduit in a first predetermineddirection.
 7. The invention according to claim 6 wherein said ventingmeans includes means for introducing air into said vacuum chamber andfor causing said air to flow from said vacuum chamber through said firstconduit in the same direction as the flow of air in said first conduitduring evacuation of said package.
 8. The invention according to claim 7wherein said first conduit includes means for trapping materialwithdrawn from said vacuum chamber.
 9. The invention according to claim8 wherein said means for venting said vacuum chamber includes means forcausing the material remaining in said first conduit subsequent toevacuation of said package to move toward said trap means.
 10. Theinvention according to claim 1 further comprising means for maintaIningsaid package in proper position relative to said vacuum chamber.
 11. Theinvention according to claim 10 wherein said means for keeping saidpackage in proper position includes means for applying a vacuum to saidpackage.
 12. The invention according to claim 11 further comprisingmeans for removing said package.
 13. The invention according to claim 12wherein said means for removing said package includes means for applyingair pressure against said package.